Tan Zi Jie(30)2P1

Chromium oxide


Heating with chlorine and carbon yields chromium(III) chloride:

Cr₂O₃ + 3 Cl₂ + 3 C → 2 CrCl₃ + 3 CO

Because of its considerable stability, chromia is a commonly used pigment and was originally called viridian. It is used in paints, inks, and glasses. It is the colourant in "chrome green" and "institutional green." Chromium(III) oxide is the precursor to the magnetic pigment chromium dioxide.


Chromium oxide can be converted into elemental chromium metal through a thermite-like reaction: unlike iron oxide thermites, chromium oxide thermites creates few or no sparks, smoke or sound, but glow brightly. Because of the very high melting point of chromium, chromium thermite casting is impractical.